Combination lock for engine starters

ABSTRACT

A combination lock for engine starters in which a combination of digits must be successively entered at a keyboard to move a locking member having a pawl through a number of positions in which the pawl interferes with the closing of the engine&#39;&#39;s starter solenoid to one position in which the pawl does not so interfere, and the locking member being normally spring urged toward an interfering position of the pawl to which the pawl is returned after the solenoid has been successfully closed, or as a result of the entry of an erroneous combination.

United States Patent [191 Theobald 1 Dec. 3, 1974 [54] COMBINATION LOCKFOR ENGINE 3,718,202 2/1973 Brock 307/10 AT X STARTERS 3,738,444 6/1973Roby 307/10 AT X Inventor: Eugene J. Theobald, 51 Forest Ave., FortThomas, Ky. 41075 Filed: July 17, 1973 Appl. No.: 380,121

US. Cl. 70/255, 70/278, 307/10 AT Int. Cl. B60r 25/04, E05b 65/12 Fieldof Search 70/255, 277, 278, 283; 200/43, 45; 307/10 AT; 317/134;335/253; 310/49 A, 49 R, 67

References Cited UNITED STATES PATENTS 7/1950 OBrien et a1. .1. 335/2533/1959 Noztitz 307/10 AT UX 5/1966 Siegel 70/255 X 2/1971 Ott 310/67 XPrimary Examiner-Robert L. Wolfe Attorney, Agent, or FirmArthur E.Dowel], Ill

[57] ABSTRACT A combination lock for engine starters in which acombination of digits must be successively entered at a keyboard to movea locking member having a pawl through a number of positions in whichthe pawl interferes with the closing of the engine's starter solenoid toone position in which the pawl does not so inter- I fere, and thelocking member being normally spring urged toward an interferingposition of the pawl to which the pawl is returned after the solenoidhas been successfully closed, or as a result of the entry of anerroneous combination.

7 Claims, 9 Drawing Figures PATENTELBEB 3W 335L504 SHEEI 10? 2 K x 6mmmmsa u PATENTEb 3 74 SHEH'EUF 2 COMBINATION LOCKFOR ENGINE STARTERSFIELD OF- INVENTION This invention relates to locking means to controlthe use of a vehicle having an engine, and to prevent use of it byunauthorized persons or prevent use of it by a person whose coordinationor manual dexterity is impaired, for instance, by intoxication, druguse, or emotional upset. More particularly, the invention relates to anovel combination lock for the engine starter system which can beunlocked by keyboard insertion of a multiple digit number in a certainsequence without error during insertion.

BACKGROUND AND PRIOR ART Because of the heavy loss of life on thehighways in recent years there has been an increased effort to preventpersons from driving vehicles who are not in full control of theirfaculties, and there have been devices suggested for preventing avehicle from being driven by a person unless he canperform apredetermined series of functions as a condition precedent to drivingthe vehicle. Some such systems require the errorless entry of apermutation of numbers into a keyboard within the vehicle prior tostarting it, and the present invention is of this latter type.

THE INVENTION This disclosure teaches a mechanism in which the startersolenoid of the engine is modified and several parts added thereto, sothat a pawl riding in a slot in the solenoid plunger is normally springurged to a position in the slot in which the pawl prevents the solenoidplunger from responding when the solenoid winding is energized. Astepping motor is used to change the position of the pawl in the slottoa position permitting the solenoid plunger to close, but only if thestepping motor is steppedthrough multiple positions without any error.Otherwisefthe" spring immediately returns the pawl to'th'e disablingposition and the expectantdriver is defeated. Individual push-buttonelectric switches on the keyboard are used to energizethe steps oftheste'pping motor, and the sequence in which they are depresseddetermines the succession of steps through which the stepping motor isactuated by a person trying to move the pawl to the solenoid-enablingposition. The structure of the stepping motor is such that its armaturecan advance only one incremental step at a time when a new step actuatorwinding is energized, so that if the person pushes the buttons in thewrong sequence, the error will release the armature to be returned toits initialposition by the spring.

It is a major object of this invention to provide an engine starter lockwherein'the steps which actually occur in response to the keyboard entryof a series of digits comprise mechanical movements of parts which arelocated at and within the solenoid, the latter being inaccessiblylocated under the hood, generally in the vicinity of the starter motor,and out of sight to thwart efforts to defeat the lock by a person tryingto observe the positions of parts or by adding jumpers to the wiring. Insome prior art systems, especially where the sequence is decoded byelectrical circuitry at the push buttons, the system can be defeated ifthe wire coming from it can be identified. In the present lock, thereare a number of wires coming from the push button unit,

but access to them is of no help to the unauthorized person, since onlythe stepping motor can decode their energization sequence.

Another major object is to provide a lock in which the mechanism isimmediately reset to an initial dormant condition whenever an error ismade in the sequence, or else as soon as the starter motor has beenoperated.

A further object is to provide a lock in which the numerical combinationof digits which must be entered, as well as their sequence, can beeasily varied to change both the required combination, and the degreeofdifficulty involved in successfully enabling the starter. It is possibleto use the same number several times in a sequence or to vary the totalnumber of digits which must be entered. Consequently, there arethousands of possible combinations. Moreover, as discussed in a laterportion of this specification, the lock is tricky to operate. Because ofthe spring constantly seeking to reset the lock to its initial state,the operator must hold the push button which was most recently presseduntil after he has pressed the next one in the sequence. If not thespring will reset the mechanism before he presses the next button andwhile the stepping motor is unenergized. Thus, more than one finger at atime must be used on the push buttons. The operation of the lock couldbe simplified by adding mechanical or electrical means for automaticallykeeping the last step energized while the next is taken, if easieraccess is required.

Still a further object of the invention is to provide a lock which usesmany of the parts already in a vehicle starter system, with only minormodifications, thereby holding down its initial cost.

Another object is to provide a starter lock equally adaptable either toDiesel or to spark fired engines.

Other objects and advantages of the present invention will becomeapparent during the following discussion of the drawings, wherein:

DESCRIPTION OF DRAWINGS FIG. 2 is a front view of the keyboard assemblyshowing the various push buttonscarried thereby;

FIG. 3 is a cross-sectional view through a conventional starter motorand solenoid showing features of the present invention added thereto;

FIG. 4 is an enlarged cross-sectional view through a stepping motorwhich forms part of the present assemy;

FIG. 5 is a detail perspective view showing the armature of the steppingmotor.

FIG. 6 is an electrical wiring diagram of the lock system;

FIG. 7 is an enlarged perspectiveview showing the starter solenoidplunger and the plunger-locking member surrounding it;

FIG. 8 is a partial sectional view taken along line 8-8 of FIG. 3 andshowing the starter motor plunger with the locking member surrounding itand geared for control by the stepping motor; and

FIG. 9 is an enlarged partial cross-sectional view taken along line 9-9of FIG. 7.

Referring now to the figures of the drawing and especially to FIG. 1,this view shows an automotive vehicle V having an engine E including astarter motor M. The

starter motor M is also seen in FIG. 3 and includes a solenoidarrangement S which is attached to the starter motor and forms a partthereof in standard automotive equipment, but which has been somewhatmodified as set forth below for present purposes. In FIG. 1, the vehicleV is also shown to include a keyboard assembly K which is connected by aseries of wires to parts which are attached to the solenoid S in themanner to be described herein below. The keyboard K has push buttons 1,2, 3, 4, and 5 comprising parts of the switches 1, 2, 3, 4, and 5 asillustrated in the wiring diagram of FIG. 6, and the keyboardalso-includes a START push button 6 corresponding with the switchlabelled 6 in FIG. 6. The switches 1 through 6 inclusive are allnormally open and are closed when their push buttons are depressed.

Referring now to FIGS. 3, 7, and 8 the solenoid S includes a plunger Pwhich is drawn to the left in FIG. 3 when the windings W of the solenoidare energized by applying electrical power to the terminal T. The coilspring C in the standard solenoid urges it to the right when thewinding-W is not energized and this also normally maintains the contactsof the electrical switch open, these contacts being labelled A and B inFIGS. 3 and 6. When the plungerP is pulled to the left by the energizingof solenoid windings W, the lever L is also pulled to the left aboutitspivot and this engages the starter gear G with the engine fly wheelteeth (not shown) in a manner well known'per se, while current throughthe contacts A and B causes the starter motor M to rotate; All of thisis of course very well known in the prior art relating to enginestarters.

It is the purpose of the present locking system to prevent the plunger Pin the solenoid S from being pulled leftwardly even though the windingsW in the solenoid may be momentarilyenergized. For this purpose, I havealtered the plung er P by millingaT-shaped slot 10, 12

into the outer surface of the plunger, this slot including 7 alongitudinal slot portion .10 joining with a circumferential'slotportion l2 as can be seen in FIGS. 7 and 8.

' In,addition,"l'have further altered the ordinary starter solenoidassembly by' puttinga guide plate 14 around the plunger, which guideplate lies against the righthand end of'the solenoid winding assembly Wand serves asan abuttment forthe left end of the .compressed coil springC'. The inner periphery 14a of the guide plate 14 is large enough sothat the plunger is free to slide through it, and the two outwardlyextending legs of the guide plate 14 are separated by a distance greatenough to receive a locking ring member 16 as can best be seen in FIGS.7, 8, and 9. The ring 16 has a pawl 18 which extends inwardly from itsinner periphery through an opening in the guide plate 14 and into theT-shaped slot l0, 12. Thus, the coil spring C presses against one leg ofthe guide plate 14 which in turn is supported against its other leg bythe end of the winding assembly W of the solenoid and therefore thespring C does not bind the rotation of the ring 16 located between thelegs 14. The other end of the coil spring C lies against an abuttment Dwhich is fixed to the plunger. I

By an inspection of FIGS. 7 and 8 it should become apparent that theplunger P cannot be pulled to the left by energizing of the winding W ofthe solenoid S unless the pawl 18 is in alignment with the longitudinalslot 10. Thus, there is only one annular position of the ring 16 inwhich the plunger P can be pulled to the left by the winding W of thesolenoid. A tension spring 20 as shown in FIGS. 7 and 8 is attachedatone end to the housing H of the solenoid S, and the other end of thespring 20 is attached to a pin 21 which extends outwardly from the ring16. As a result, the spring 20 attempts to rotate the ring clockwise asshown in FIGS. 7 and 8 unless this rotational effort is successfullyopposed by the gearing 24 and 26 shown in FIG. 8. The spring 20normallyholds the ring 16 in such a position that the pawl 18 is to oneside of the circumferential slot 12'and'therefore out of alignment withthe longitudinal slot 10 as shown both in FIGS. 7 and 8. The gear 26 onthe stepping motor 22 as shown in FIGS. 4 and 8 is connected by'an idlergear 24 to the teeth 16a in the outer periphery of the ring 16. Theseteeth do not go all the way around the ring 16, but extendmerely througha sector thereof sufficient that the stepping motor can move the pawl 18back and forth in the slot 12. The stepping motor 22 is bolted to thehousing H by screws 28, and the housing H has a small opening in itsside through which the idler, gear 24 can engage the teeth 16a of thering 16. The spring 20 is strong enough that when the stepping motor 22is not energized at the proper one of its windings, the spring can dragthe ring 16 and the gears 24 and 26 around to return'the stepping motor22 to a locking position in which the pawl 18 is located, as showninFIGS. 7 and 8, in the transverse slot 12, out of alignment withlongitudinal slot 10. The plunger P is further provided with a keywayslot 30 along its side diametrically opposite the slot 10, and a key 32is inserted in the slot 30 andinto a portion of the wall of the openingin which the plunger slides within the solenoid assembly so as toprevent the plunger from rotating, thereby maintaining the longitudinalslot 10 always in the same position with respect to the positionof thegearing 24 and 26. I v

The construction of the stepping motor 22 can best be seen in FIGS. 4,Sand 6. The stepping motor is mounted in its own housing34 and hassuitable bearings for receiving the shaft 36. ,Withinthe stepping motorhousing 34 there are located a series of spaced actuator coils, such asthe coils 38 and 40 which are shownas being among a multiplicity of suchactuator coils evenly spaced around the stepping motor. As can best beseenv in FIG. 6 the coils are equally spaced and are all connected atoneterminal to the vehicle's source of electrical power through theignition key switch F, while the other ends of the five actuator coilsincluding the coils 38 and 40 are respectively connected to the switches1 through 5 inclusive of the starter keyboard K. It should be noted thatthe coils would not be sequentially connected to the switches 1 through5 in a practical installation. Thus, a person not knowing the correctcombination would not know the sequence in which to'press the pushbuttons on the keyboard K in order to successfully actuate the coils.The effect ofactuating the coils is to pull the armature 42 aroundinside the housing 34 of the stepping motor 22, thereby rotating theshaft 36 to which the armature 42 is connected, thereby also to rotatethe ring 16. It should be especially noticed that the armature 42 isvery narrow and therefore cannot be attracted to just any position bythe energizing of just any one of the actuator coils. Because of thenarrowness of the armature 42 as measured in the circumferentialdirection of the stepping motor, the armature can be attracted only tothe next adjacent position by opening one of the switches 1 through 5and closing another one of them. If an attempt is made to attract thearmature through too great a distance circumferentially, the result willbe the same as de-energizing the stepping motor because the spring 20will return the ring 16 to its initial position as shown in FIGS. 7 and8 in which the pawl 18 is out of alignment with the slot 10. Moreover,it is possible to rotate the armature 42 too far, with the result thatthe pawl 18 goes beyond longitudinal slot 10 and into the portion of thecircumferential slot 12 lying beyond it, whereby the solenoid S whenenergized still cannot attract the plunger P to the engine startingposition.

The procedure required for starting the engine can best be explainedwith reference to the electrical diagram of FIG. 6. When the operator ofthe vehicle inserts the key into the ignition switch F and closes theswitch, the common terminal of all the actuator coils of the steppingmotor 22 will be energized, the vehicle ignition coil (not shown) willbe energized, and one side of each of the keyboard switches 1 through 6will be energized. At this time, the operator of the vehicle will presswhichever one of the keys 1 through 5 is operative attracting thearmature 42 within the stepping motor 22 to the first step position fromits rest position as established by the tension of the spring 20. Then,he will depress-the second button operating to attract the armature 42to the second step position, whereupon he will release the first pushbutton and the armature will then move to the second position pullingthe spring against it by rotating the ring 16. The operator thenproceeds through whatever other positions are required to accomplish theentire keyboard insertion of the combination, the operator on eachoccasion pressing the push button required to move the armature fromwhatever position it is presently in to the next adjacent positionbefore he releases the button which he has been holding. When at last hehas entered the entire combination, he continues to hold the last pushbutton in the pressed position while he presses the START push button 6to energize the winding W of the solenoid, which then closes the switchA, B, and engages the starter motor gear G.

' If the operator has inserted the correct combination, the pawl 18 willbe aligned with the longitudinal slot 10. Therefore the plunger willbeable to close when he pushes the START switch 6. Conversely, if theoperator has entered an incorrect combination, the pawl 18 will eitherbe located in the wrong portion of the circumferential slot 12 or willhave returned to the initial position shown in FIGS. 7 and 8 when theoperator tries to make the stepping motor take too large a step, wherebythe stepping motor loses control and the spring 20 returns the ring 16to its initial position. In either event, the operator will then have tostart all over again entering the combination.

As set forth in the objects of the invention, one of the particularadvantages of the present lock is that the decoding of the combinationis accomplished at the starter motor inside of the solenoid housing at alocation where it is impossible for anyone to see whether or not thepawl 18 has been moved into alignment with the longitudinal slot 10.Hence, it is virtually impossible to defeat the lock by observing whathappens when various ones of the push buttons 1 through 5 are depressed.

Although in the present illustrative embodiment five push buttons andfive windings have beenshown and described, it is to be understood thata larger number thereof can be employed if desired in order to make theoperation of the lock more difficult. In particular, it might bedesirable to use ten push buttons instead of only tive, and have some ofthe push buttons connected to nothing so that a person has a largerchoice of incorrect combinations. Using this approach, when a personpresses a non-connected push button, it would result in complete releaseof the stepping motor to return the lock to its initial inoperativeposition.

The present invention is not to be limited to the specific embodimentillustrated in the drawings, for obviously changes in the lock can bemade within the scope of the attached claims.

I claim:

1. A combination lock for a vehicle engine having a starter mechanismincluding a starter solenoid having a reciprocable plunger adapted to bedrawn from an initial rest position to an engine-starting position whenthe solenoid winding is energized, the lock comprising:

a. a locking member supported by the starter solenoid and including apawl, the member being moveable through multiple possible positionswherein the pawl interferes with reciprocation of the plunger intostarting position and said multiple positions including one intermediateposition in which the pawlfrees the plunger to move into startingposition; spring means operative to bias the locking member and pawlaway from said one position;

c. motor means operative to move through steps and coupled to move thelockingmember pawl through said multiple positions including saidintermediate position, the motor means including an actuator coil foreach step capable when energized of moving the motor means into thecorresponding position, and the motor means having its positiondetermined by said spring means when none of its coils is energized; andI keyboard means having multiple push buttons at least some of which areconnected to energize the various motor coils, and the vehicle includingmeans to energize the starter solenoid.

2. The combination lock as set forth in claim 1, wherein said solenoidcomprises a housing containing said plunger, and said plunger has alongitudinal slot extending longitudinally along its side, and saidlocking member comprising a ring mounted for rotation on said housingand surrounding said plungenthe pawl being fixed to the ring andmoveable with rotation of the latter into said multiple possiblepositions, in one of which the pawl is in alignment with the slot.

3. The combination lock as set forth in claim 2, wherein the slot isT-shaped and the longitudinal slot joins a circumferential slot locatedto receive the pawl when the solenoid is de-energized.

4. The combination lock as set forth in claim 3, wherein the springmeans is coupled between the housing and the ring, and normally urgesthe ring into a rotational position in which the pawl is in thecircumferential slot of the plunger, out of alignment with itslongitudinal slot.

5. The combination lock as set forth in claim 2, wherein said ringhaving gear teeth on its outer periphery and the housing having anopening in it opposite said teeth, and the motor having a shaft coupledto said ring by gear means meshing with said teeth.

6. The combination as set forth in claim 5, wherein said motor meansincluding an armature mounted on the returning force of the springrelative to the torque of the motor means is such that when one coil isenergized and a push button is erroneously pressed energizing anon-adjacent coil, upon de-energizing of said one coil, the spring meanswill return the ring to an interfering position in which the pawl is outof alignment with the slot.

1. A combination lock for a vehicle engine having a starter mechanismincluding a starter solenoid having a reciprocable plunger adapted to bedrawn from an initial rest position to an engine-starting position whenthe solenoid winding is energized, the lock comprising: a. a lockingmember supported by the starter solenoid and including a pawl, themember being moveable through multiple possible positions wherein thepawl interferes with reciprocation of the plunger into starting positionand said multiple positions including one intermediate position in whichthe pawl frees the plunger to move into starting position; b. springmeans operative to bias the locking member and pawl away from said oneposition; c. motor means operative to move through steps and coupled tomove the locking member pawl through saiD multiple positions includingsaid intermediate position, the motor means including an actuator coilfor each step capable when energized of moving the motor means into thecorresponding position, and the motor means having its positiondetermined by said spring means when none of its coils is energized; andd. keyboard means having multiple push buttons at least some of whichare connected to energize the various motor coils, and the vehicleincluding means to energize the starter solenoid.
 2. The combinationlock as set forth in claim 1, wherein said solenoid comprises a housingcontaining said plunger, and said plunger has a longitudinal slotextending longitudinally along its side, and said locking membercomprising a ring mounted for rotation on said housing and surroundingsaid plunger, the pawl being fixed to the ring and moveable withrotation of the latter into said multiple possible positions, in one ofwhich the pawl is in alignment with the slot.
 3. The combination lock asset forth in claim 2, wherein the slot is T-shaped and the longitudinalslot joins a circumferential slot located to receive the pawl when thesolenoid is de-energized.
 4. The combination lock as set forth in claim3, wherein the spring means is coupled between the housing and the ring,and normally urges the ring into a rotational position in which the pawlis in the circumferential slot of the plunger, out of alignment with itslongitudinal slot.
 5. The combination lock as set forth in claim 2,wherein said ring having gear teeth on its outer periphery and thehousing having an opening in it opposite said teeth, and the motorhaving a shaft coupled to said ring by gear means meshing with saidteeth.
 6. The combination as set forth in claim 5, wherein said motormeans including an armature mounted on said shaft, and said actuatorcoils being mounted in successive annular positions around said shaft,the coils and the armature being placed and shaped such that a newlyenergized coil can attract the armature to step to it only if thearmature is already at an immediately adjacent position.
 7. Thecombination as set forth in claim 6, wherein the returning force of thespring relative to the torque of the motor means is such that when onecoil is energized and a push button is erroneously pressed energizing anon-adjacent coil, upon de-energizing of said one coil, the spring meanswill return the ring to an interfering position in which the pawl is outof alignment with the slot.